ATHENS, Greece -- The United Nations refugee agency is urging Greece's government to provide separate housing and washing facilities for women and children at island refugee camps, citing the risk of sexual violence.

The UNHCR says it has received reports from about 180 camp residents who say they have suffered some form of sexual or gender-based violence after arriving in Greece.

In 2017, we received reports from 622 survivors of sexual and gender-based violence on the Greek Aegean islands, out of which at least 28% experienced #SGBV after arriving in Greece. https://t.co/uA7i1E9Sax

A UNHCR statement Friday said the situation is particularly worrying in the crowded refugee camps of Moria on Lesvos and Vathy on Samos, where toilets and washing facilities are "no-go zones" after dark for unaccompanied women and children.

It cited a woman in Moria who said she had not showered for two months for fear of attack.